Brake System Fundamentals Flashcards
A force of 800 N applies to a master cylinder with an area of 8.0cm2. Calcualte the system pressure in kPa.
1000 kPa
A brake system develops 350 psi on application. The force produced at a caliper piston with an area of 2.75 in2 is:
a) 127.27 lb
b) 1227.27 psi
c) 962.5 lb
d) 962.5 psi
c) 962.5 lb
A 2.5 cm diameter master cylinder is replaced with a 5.0 cm diameter master cylinder. The result is:
a) more pressure in the system
b) more force at the calipers
c) less pressure in the system
d) more force at the wheel cylinders
c) less pressure in the system
One reason DOT 5 brake fluid is not recommended for ABS systems is because it:
a) has a higher boiling point
b) has a lower boiling point
c) harms painted surfaces
d) is not hygroscopic
d) is not hygroscopic
The gylcol-based brake fluid that has the highest boiling point is _____________.
DOT 4
The automotive brake system converts kinetic energy to heat energy through:
a) friction
b) hydraulics
c) electronics
d) air pressure
a) friction
Why should brake fuild be stored only in a sealed container?
Becasue the fuild is hygroscopic
What are the three (3) things that friction between two sliding surfaces depends on?
1) the amount of force pressing the two surfaces together
2) the temperature of the surfaces in contact
3) the coefficient of friction of the materials in contact
Pressure in an enclosed liquid:
a) varies with the size of the container
b) varies with the shape of the container
c) acts with equal force on equal areas
d) acts parallel to the surface
c) acts with equal force on equal areas
The wheel cylinders and calipers converts pressure developed in the system into:
a) heat
b) mechanical force
c) directional pressure
d) static friction
b) mechanical force
The force that tends to resist motion between objects in contact is called ________
friction
The energy forms primarily present in the braking system are _______ energy and ______ energy.
kinetic heat
What is the law of conservation of energy?
Energy can neither be created nor destroyed
What is kinetic energy?
The energy of a mass due to motion - depends on mass and velocity (speed)
If two objects are travelling at the same speed, but object 1 has twice the mass of object 2, how much kinetic energy does object 1 have?
Object 1 would have twice the kinetic energy.
If two objects are equal mass, but object 1 is travelling at twice the speed as object 2, how much kinetci energy does object 1 have?
Object 1 would have 4 times the kinetic energy as object 2
What is conduction?
Heat transfer between objects in contact with each other.
What is convection?
Heat transfer that applies to fluids (liquids or gases). It’s the movement of the fluid that is being heated due to a change in its density.
What is forced convection?
Forced convection occurs when mechanical means aid fluid movement. - It is the primes cooling method in brake systems. It’s created using fins.
What are air scoops used for?
they use the forward motion of the vehicle to move air over and through the brake components for cooling.
What is infrared radiation?
a form of light energy. transfers heat without direct contact between objects.
What is a heat sink?
a heat storage device (a large mass) used to help dissipate heat.
What is friction?
The resistance to movement
What is a coefficient of friction (COF)?
A number representing the relative amount of friction between two surfaces.
What happens to the coefficient of friction between the brake linings and the drum/rotor as the linings heat up?
The COF goes down
What is brake fade?
occurs when the lining and the drums or disc overheat so severely that the friction between them virtually disapperas.
What is static friction?
the friction between two stationary objects
What is kinetic friction?
The friction between two surfaces that have relative motion between them.
What is regenerative (regen) braking?
during braking, a generator converts the vehicle’s kinetic energy ino electricl energy. The torque required to spin the generator slows the vehicle down and the energy produced charges a large storage battery.
What is hygroscopic?
The ability to absorb moisture.
In a brake system, the amount of force that the fluid pressure enerates depends directly on the amount of ___________ in the system and the the working _______
Pressure - Surface area
What two units is pressure measure in?
Pascals (Pa) and pounds per square inch (psi)
What is one Pascal?
the pressure developed when a force of one newton is applied over an area of one square metre. 1 Pa = 1 N/m2
What is 1 psi
The force of 1 lb applied over and area of 1 in2
What is the formula for pressure?
p = F / A
F = the force applied
A = the area of the reaction surface
